1. Field of the Invention
This invention relates to a process cartridge detachably mountable to an electrophotographic image forming apparatus. This invention further relates to a connecting pin for pivotally connecting two frames in the construction of the process cartridge.
The electrophotographic image forming apparatus forms an image on a recording medium by the use of the electrophotographic image forming process. Examples of the image forming apparatus include electrophotographic copiers, electrophotographic printers (such as laser beam printers and LED printers), facsimile apparatuses and word processors.
Also, the process cartridge may refer to charging means, developing means or cleaning means and an electrophotographic photosensitive drum integrally made into a cartridge which is made detachably mountable to the main body of the image forming apparatus. Alternatively, the process cartridge may refer to at least one of charging means, developing means and cleaning means and an electrophotographic photosensitive drum integrally made into a cartridge which is made detachably mountable to the main body of the image forming apparatus. Further alternatively, the process cartridge may refer to at least developing means and an electrophotographic photosensitive drum integrally made into a cartridge which is made detachably mountable to the main body of the image forming apparatus.
2. Description of the Related Art
In an image forming apparatus using the electrophotographic image forming process, there has heretofore been adopted a process cartridge into which an electrophotographic photosensitive member and process means for acting the electrophotographic photosensitive member are integrally made and which is made detachably mountable to the main body of the image forming apparatus. According to the process cartridge system, the maintenance of the apparatus can be done by a user himself without resort to a serviceman and therefore, the usability of the apparatus is markedly improved.
As a typical construction of such a process cartridge, there is one in which two frames are connected together. For example, a cleaning frame supporting a photosensitive drum, a charger and a cleaning device, and a frame comprising a developing frame supporting developing means and a toner frame having a toner chamber, the developing frame and the toner frame being joined together, are connected together for rotation about a fulcrum. The two frames are biased about the fulcrum by a resilient member such as a spring to thereby determine the relative position of the photosensitive drum and the developing means. The functional merits of adopting the above-described construction include many merits such as the optimization of the pressure force of a developing roller against the photosensitive drum, and the maintenance of the interval between the surface of the photosensitive drum and the surface of the developing roller, as well as the ease of the molding of the frames by the division into two, and the ease of assembly.
The present invention is a further development of the aforedescribed conventional art.
It is an object of the present invention to provide a connecting pin improved in connecting strength, and a process cartridge using the connecting pin.
It is another object of the present invention to provide a connecting pin difficult to pull out, and a process cartridge using the connecting pin.
It is another object of the present invention to provide a connecting pin improved in the reliability of connection, and a process cartridge using the connecting pin.
It is another object of the present invention to provide a connecting pin and a process cartridge practically using an improvement in pull-out strength, and particularly providing an improvement in strength to endure (i.e., not slipping out) vibration or shock applied thereto in the physical distribution process.
It is another object of the present invention to provide the connecting pin for a process cartridge and a process cartridge which enable stringent quality control such as periodical sampling inspection of the surface roughness and force-fit strength of the connecting pin so that a predetermined force-fit strength may be secured to be saved.
It is another object of the present invention to provide the connecting pin for a process cartridge which is formed of a metallic hollow material and a portion of which is formed with such a restraining portion that the trailing end thereof juts outwardly with the leading end thereof with respect to the direction of insertion as a bending proximal base by bending, and a process cartridge.
It is another object of the present invention to provide a process cartridge having a first frame supporting an electrophotographic photosensitive drum, a second frame supporting developing means, and a connecting pin which is formed of a metallic hollow material and a portion of which is formed with such a restraining portion that the trailing end thereof juts outwardly with the leading end thereof with respect to the direction of insertion as a bending proximal base by bending, and which pivotally fits the first frame and the second frame to each other.
These and other objects, features and advantages of the present invention will become more apparent upon consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.